| Skyview Property & Developments Ltd | Construction | 2025 |
| Skywide Design Limited | Information & communication | 2004 |
| SL Firm UK Limited | Construction | 2014 |
| SL Labour Ltd | Other services | 2024 |
| Slanting Arrow Limited | Administrative & support | 2006 |
| SLE Solutions Ltd | Administrative & support | 2026 |
| SLN (London) Ltd | Wholesale & retail | 2019 |
| Slumbernightsuk Ltd | Other services | 2025 |
| Slyde Body Limited | Wholesale & retail | 2024 |
| SM Transport Consulting Ltd | Professional & scientific | 2019 |
| Small Places Records Ltd | Information & communication | 2025 |
| Smart Audio Visual Limited | Professional & scientific | 2021 |
| Smart Audio Visual Services Limited | Professional & scientific | 2009 |
| Smart Buildings Service Limited | Construction | 2021 |
| Smart Capital Corporate Director Limited | Administrative & support | 2025 |
| Smart Capital Nominees Limited | Administrative & support | 2025 |
| Smart Managed Services Ltd | Extraterritorial | 2017 |
| Smart Property Refurbishments Ltd | Construction | 2024 |
| Smart Street Furniture Limited | Professional & scientific | 1996 |
| Smart Surveillance Solutions Limited | Administrative & support | 2019 |
| Smart Urban Living Bristol (One) Limited | Construction | 2023 |
| Smart Urban Living Bristol (Two) Limited | Construction | 2023 |
| Smart Urban Living Streatham Limited | Construction | 2025 |
| Smart Way Forward Ltd | Extraterritorial | 2011 |
| Smart Works Systems Limited | Information & communication | 2015 |
| Smartcleanuk Limited | Administrative & support | 2024 |
| Smartsourcegb Ltd | Information & communication | 2010 |
| Smartys Day Nursery (Hitchin) Ltd | Education | 2016 |
| Smashzone Sports Ltd. | Wholesale & retail | 2024 |
| SMB Spray Renders Ltd | Construction | 2024 |
| Smcs Limited | Professional & scientific | 2000 |
| SMG Engineering Ltd | Manufacturing | 2018 |
| SMH Therapy and Consultancy Ltd | Health & social care | 2024 |
| Smidoo Ltd | Wholesale & retail | 2010 |
| Smith and Wardle Financial Consultants LLP | | 2015 |
| Smith and Wardle Ltd | Financial services | 2025 |
| Smiths 1972 Limited | Professional & scientific | 2012 |
| Smordei Limited | Professional & scientific | 2022 |
| Smurners Limited | Real estate | 2016 |
| SN Power Services Limited | Construction | 2025 |
| Snacks on Legs Limited | Extraterritorial | 2008 |
| SNM Property Solutions Limited | Real estate | 2024 |
| Snowflake Estates Limited | Real estate | 2021 |
| Soak and Scrub Ltd | Manufacturing | 2024 |
| Soaring Salmon Ltd | Hospitality | 2023 |
| Social Done for YOU Limited | Professional & scientific | 2024 |
| Social Justice Limited | Health & social care | 2021 |
| Social Spheres Innovation Ltd | Professional & scientific | 2024 |
| Socialise Digital Limited | Information & communication | 2019 |
| Society for Dialectical Behaviour Therapy | Other services | 2012 |
| Society for Distributing Hebrew Scriptures(The) | Other services | 1952 |
| Socomec Limited | Manufacturing | 1993 |
| Sofa Assist Ltd | Other services | 2020 |
| Sofa Sessions Limited | Health & social care | 2023 |
| Soft Serenity Interiors Ltd | Professional & scientific | 2025 |
| Softdynamix Ltd. | Information & communication | 2015 |
| SOL Investment Properties Ltd | Real estate | 2021 |
| SOL Lounge Bar Ltd | Hospitality | 2020 |
| SOL Permanent Cosmetics Limited | Other services | 2019 |
| Solace Electrical Limited | Construction | 2012 |
| Solcryos Limited | Wholesale & retail | 2024 |
| Solfege Media Ltd | Information & communication | 2011 |
| Solm Systems Ltd | Information & communication | 2025 |
| Solmheart Vault Ltd | Professional & scientific | 2025 |
| Soltech Holdings Limited | Financial services | 2021 |
| Solution Consulting Engineers Ltd | Professional & scientific | 2011 |
| Somewhere Junction Ltd | Information & communication | 2024 |
| Sooprayen Consulting Ltd | Information & communication | 2016 |
| Sophie Medley Ltd | Real estate | 2025 |
| Soul Club Media Limited | Information & communication | 2016 |
| Soundtrack Creation Limited | Information & communication | 2013 |
| Sourcec.Com Limited | Administrative & support | 2003 |
| South Cambs Landscapes Limited | Administrative & support | 2011 |
| South COL Ltd. | Information & communication | 2006 |
| South Living Limited | Real estate | 2016 |
| South London Medical LLP | | 2025 |
| Southern Commercial Truck & Trailer Repairs Ltd | Manufacturing | 2012 |
| Southern Commercials Fleet Services Limited | Wholesale & retail | 2018 |
| Southern Premier Solutions Ltd | Construction | 2018 |
| Southolme Consulting Limited | Professional & scientific | 2015 |
| Southwark Park Freehold Limited | Real estate | 2013 |
| Southwark Park Leasehold Limited | Real estate | 2013 |
| Southwood Developments Limited | Construction | 2016 |
| SOW CIC | Other services | 2025 |
| SP Electrical Engineering Services Ltd | Professional & scientific | 2024 |
| SPACE2PLAY (Herts) Limited | Arts & recreation | 2009 |
| Spacecadet Design Limited | Professional & scientific | 2015 |
| Spacecraft Systems Engineering Ltd | Manufacturing | 2011 |
| Spandrel Brickwork Ltd | Construction | 2018 |
| Sparkle Innovation Limited | Wholesale & retail | 2025 |
| Sparkle Town Limited | Wholesale & retail | 2020 |
| Sparkles and Smiles Ltd | Education | 2020 |
| Spd-S Europe Limited | Professional & scientific | 2015 |
| Specialised Associates Limited | Real estate | 1992 |
| Specialist K9'S Limited | Administrative & support | 2020 |
| Specialist Portal Solutions Limited | Professional & scientific | 2015 |
| Specialist Therapy Limited | Financial services | 2012 |
| Specialist Traders Limited | Wholesale & retail | 2023 |
| Specifically Learning Ltd | Education | 2022 |
| Spectrum One Limited | Professional & scientific | 2011 |